1. Field of the Invention
The present invention relates to a disk-type magnetic recording/reproducing apparatus which can be well used as a storage apparatus of a computer or as a storage apparatus for storing audio and video information.
2. Description of the Related Art
A motor employed in a tape-type magnetic recording/reproducing apparatus as a rotation driving means is designed into a mechanism wherein the characteristic of the motor can be switched from a low speed to a high speed in dependence on some types of rotation mode. In the case of a portable tape recorder, for example, one motor is used to drive a tape to travel at a low speed in a reproduction (playback) or recording operation and at a high speed in a fast-feeder rewind operation in neither a recording mode nor a reproduction mode. In order to implement the function to drive a tape at different speeds as described above, there is adopted a method whereby the characteristic of the motor is switched from a constant-speed (low-speed) state to a high-speed state and vice versa so as to allow the driven tape to travel well as is generally known.
In general, a disk-type magnetic recording/reproducing apparatus such as an apparatus for driving a floppy or hard disk used as an external storage device of a personal computer adopts a CAV (Constant Angular Velocity) system wherein the rotational angular velocity of a spindle motor serving as a rotation driving means is fixed.
In the case of a floppy disk, some floppy-disk drives adopt a CLV (Constant Linear Velocity) system wherein the rotational speed is varied from track to track to result in a fixed scanning velocity independently of the radial position of the head. The CAV and CLV systems are different from each other in that, in the case of the former, the scanning speed of the head is fixed while, in the case of the latter, the scanning speed of the head is variable. In the case of both the systems, however, only a single performance can be displayed as an operating mode allowing recording/reproduction operations.
It should be noted that, in the case of the CLV system, the ratio of a maximum rotational speed to a minimum rotational speed of a disk is equal the ratio of the radius of an outermost circumference of a data area on the disk for recording data to be reproduced later to the radius of an innermost circumference of the data area. That is, if the ratio of the outer-circumference radius to the inner-circumference radius of the data area is 2, the ratio of a maximum rotational speed to a minimum rotational speed of a disk is also 2. However, changes to rotational speed are controlled by a means for making the scanning speed of the head relative to the disk medium fixed and there is displayed only one recording/reproduction performance in a constant-speed recording/reproduction operating mode. That is, even if the rotational speed is changed, the recording/reproduction operating mode does not produce different kinds of recording/reproduction performance.
As such, in the prior art, there is no disk-type magnetic recording/reproduction apparatus which has a recording/reproduction operating mode providing different kinds of recording/reproduction performance at more than one rotational speed.
First of all, consider a hard-disk drive, a representative disk-type magnetic recording/reproduction apparatus. There are two kinds of hard-disk drive with a constant rotational speed: a hard-disk drive with a low rotational speed referred to hereafter as a low-speed disk drive and a hard-disk drive with a high rotational speed referred to hereafter as a high-speed disk drive. Differences between the low-speed disk drive and the high-speed disk drive are explained as follows.
The low-speed disk drive has an excellent power-consumption characteristic and an excellent rise time from a sleep mode in an operation to read a TOC (Table of Contents) or a FAT (File Allocation Table) used as an area for controlling data recording in files. That is, the rise time that results with the power consumed by the motor kept constant can be shortened and a motor cost for making the rise-time speed fixed as well as the amount of consumed power can be reduced.
On the other hand, the high-speed disk drive has an excellent capability of transferring data at a high transfer speed due to the fact that the disk is rotated at a high rotational speed.
Thus, a low-speed disk drive is not so good as a high-speed disk drive in that data can not be transferred at a high speed. However, the low-speed disk drive is convenient in that it can be employed in a portable apparatus due to the fact that the low-disk drive can be implemented with low power consumption. In addition, since it is difficult to implement a high-speed disk drive at low power consumption, the high-speed disk drive is not appropriate for a portable application wherein a long life of the battery thereof is desired. Nevertheless, the high-speed disk drive is capable of transferring data at a high speed.
It is thus an object of the present invention to provide a recording/reproduction method and a recording/reproduction apparatus that are capable of transferring data at a high speed and, at the same time, implementing low power consumption.
In order to achieve the object of the present invention described above, the present invention provides a recording/reproduction method for recording and reproducing information into and from a magnetic disk driven to rotation whereby, as recording/reproduction operating modes of the magnetic disk, the method is provided with a plurality of drive modes for different kinds of performance including at least a low-speed drive mode and a high-speed drive mode.
In addition, in order to achieve the object of the present invention described above, the present invention also provides a recording/reproduction apparatus for recording and reproducing information into and from a magnetic disk driven to rotation. The recording/reproduction apparatus is provided with at least a rotation driving unit for driving the magnetic disk to rotation and a control unit for controlling the rotation driving unit wherein the control unit is capable of controlling the rotation driving unit in a plurality of operating modes for different kinds of performance including at least a low-speed drive mode and a high-speed drive mode so as to drive the magnetic disk to rotation.
In the recording/reproduction method and the recording/reproduction apparatus provided by the present invention, when an operation in a high-speed mode is completed, first of all, the speed is reduced to a value in a low-speed mode before writing information into the TOC/FAT and then the speed is further reduced to halt the rotation of the magnetic disk.
As an alternative, when an operation in a high-speed mode is completed, information is written into the TOC/FAT with the speed sustained at a value in the high-speed mode and then the speed is reduced to halt the rotation of the magnetic disk.
As another alternative, when an operation in a high-speed mode is completed, information is written into the TOC/FAT with the speed sustained at a value in the high-speed mode and then the rotation of the magnetic disk is halted from the rotation in the high-speed mode.
In addition, in a start/halt system wherein a head is loaded and unloaded to and from the magnetic disk in a non-contact way, the rotational speed at which the magnetic disk is rotating at the time an operation is being started or halted is set at a value in the low-speed mode or a value in a low-power-consumption mode. As an alternative, the rotational speed at which the magnetic disk is rotating at the time an operation is being started or halted can be set at a value lower than that of the low-speed mode.
As another alternative, the rotational speed at which the magnetic disk is rotating at the time an operation is being started can be made different from the rotational speed at which the magnetic disk is rotating at the time an operation is being halted.
In addition, power supplied by a battery can be distinguished from power supplied by a commercial power supply provided by an electric-power company and, in an operation driven by power supplied from the battery, the recording/reproduction apparatus is set in an operating mode with low power consumption.
As described above, the recording/reproduction apparatus provided by the present invention has a plurality of recording/reproduction modes for different kinds of performance including at least a low-speed drive mode and a high-speed drive mode. As a result, when a transfer of data at a high speed is required, the recording/reproduction apparatus is switched to a high-speed drive mode for implementing the high-speed data transfer and, when power saving is needed, the recording/reproduction apparatus is switched to a low-speed drive mode for implementing the power saving.
In addition, power saving and operations to read out information from the FAT/TOC at a high speed can be implemented in the same apparatus.